doc: update readme

README.md

@@ -1,9 +1,53 @@
+[![Actions Status](https://github.com/konradmalik/baywatch/actions/workflows/main.yml/badge.svg)](https://github.com/konradmalik/baywatch/actions)
+
 # baywatch
 
 Watch files and execute commands if they change.
 
+## Installation
+
+```
+$ cargo install --locked baywatch
+```
+
+or
+
+Use the provided package via flake
+
+or
+
+```
+$ nix build
+```
+
+or
+
+```
+$ nix run
+```
+
+## Usage
+
+```bash
+$ bwatch --help
+```
+
+Simplest example:
+
+```bash
+$ bwatch -- ls -lah
+```
+
 ## Assumptions
 
--   simple
+-   simple codebase and usage
 -   sane defaults
-    -   like using local gitignore properly
+    -   using local gitignore properly
+    -   ignores change events that happened since starting the scheduled command (not running tests 10 times if files changed
+        10 times)
+    -   streams stdout and stderr
+-   tested and used only on Linux and Darwin, may or may not work on Windows
+
+## Similar to
+
+-   [watchexec](https://github.com/watchexec/watchexec)